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By John C. McDonald

CONTROLLED cold work is used between solution heat treatment and precipitation heat treatment for producing certain tempers of the commercial aluminum base alloy 2219 (designation of the Aluminum Association, U.S.A.) which contains 6.3 pet Cu as the major ingredient responsible for the age hardening. The complete composition limits for this alloy are listed in Table I. The alloy has been described in detail,' and the control of the heat treatment has also been published.2 Beneficial effects of such cold work in other alloys have also been pointed out.3'4 NO data have been published on the effects of varying amounts of cold work under fixed aging conditions. In connection with an investigation of the possibility of providing the desired cold work by explosively generated shock waves, it became desirable to investigate the effect of variable cold work, and to compare the re -sults with those obtained from explosives. The general principles of explosive hardening are well-described in the literature.' All material used was guaranteed by the supplier

Jan 1, 1968

By William J. Robinson

What is the cummulative rate of recovery of copper from a sulfide leach dump? The technical answers to this frequently asked question may vary from "I don't know" to "quite good" from people of the same company. Management also poses this question because it plays a vital role in planning future production. The answer is difficult because of the many variables between different operations such as physical construction of the dump, topography of the original site, characteristics of dump material, mineralization and water application. Each of these factors and others have a bearing on the rate of recovery. Anaconda's method of water distribution at Butte is unique in that each dump is drilled to allow physical injection of water into the dump. The injection holes are drilled vertically on 25 ft centers from the surface of the dump. Normally, the holes are drilled 40 ft deep and cased with 4-in. PVC perforated pipe. The pipe is perforated at one-foot intervals with four 1/2 in. diam holes at 90" spacing on the pipe circumference.

Jan 9, 1972

By A. M. Gaudin, R. T. Hukki

PREVIOUS work on the principles of comminution has shown: (I) that the surface produced is proportional to work input (Rittinger law, 1a-3); (2) that there is regularity to the weight distribution of the fragments according to size.4-10 In this paper it is brought out that the surface on the fragments is distributed in definite and simple relation to size. The experimental work has involved: I. Construction of an apparatus capable of measuring the surface of mineral fragments independently of the chemical composition of the fragments and independently of the site of the surface; 2. Refining the methods available for measurement of particle size; 3. Designing and building a crusher capable of operating on very small quantities of mineral, if necessary on single crystals, and in such fashion as to minimize handling losses of material. Complete experiments have been carried out with massive quartz and individual quartz crystals. Partial experiments, lacking surface measurements, have been made with glass spheres, galena, sphalerite, fluorite, salt and coal.

Jan 1, 1944

By Jack C. Jones, Hemendra N. Kalia

This paper is partially based on a comprehensive ground control investigation that was conducted by Harza Engineering Company under a contract from the Bureau of Mines. This investigation required in- stalling several types of ground movement indicating devices on the surface and in the mine. The major instrumentation systems consisted of hydraulic borehole pressure cells, multi-point extensometers, in- clinometers, convergence indicators, Jack pressure recorders time domain reflectometers, and a 200 station subsidence network. The investigation demonstrated the versatility of the system. We were able to install pressure cell s to a depth of over 200 feet in the coal bed and we were successful in installing 10 pen mechanical recorders to monitor differential strata movement. In this paper, we have briefly discussed data from 18 borehole pres- sure cells, two time domain reflectometer cables and four subsidence lines. The data collected showed that the front and rear abutment pressures were approximate1 y 1000 feet (304.81~1) to 1200 feet (356.76111) from the active face. The peak pressure was about 4 times the over- burden pressure.

Jan 1, 1983

By R. G. Carlson, F. E. Westermann

HOT pressing of powder particles has gained importance recently, since it affords a method in which high densities are rapidly attained. In a recent study on hot pressing of alumina powders, Mangsen, Lam-bertson, and Best1 have shown within the limits of their experiment, the validity the rate equation for densification in hot pressing, originally proposed by Murray, Livey, and Williams.2 i.e., where D = fraction of theoretical density, t = time, P = pressure and 77 is the viscosity, all in appropriate units. This equation was derived from earlier work of Shuttleworth and Mackenzie3 which is based on the closing of spherical pores under the action of surface tension. The integrated form of this equation yields a straight-line relation between log (1 - D) and t. Such conditions were found by Felten4 to be true only after extended periods of pressing. In an endeavor to quantitatively evaluate the exactitude of this equation in the initial sintering stage, i.e., prior to sealing of the pores, spherical anti-

Jan 1, 1962

By D. B. Crouch, D. A. Poulter

The engineering and metallurgical assessment of the McLaughlin Project ore body concluded that an open-pit mine and cyanide leach mill process would be feasible, producing both waste rock and residual mill tailings. As a part of the planning and permitting process, site selection studies were conducted for the tailings and waste rock disposal. The site selection process began with a regional identification of potential disposal sites and proceeded through 1) regional screening, 2) elimination of sites with obvious fatal flaws, 3) qualitative ranking of site evaluation criteria, 4) quantitative ranking of sites, 5) field investigation, 6) evaluations of field data, and 7) selection of preferred sites. Based on this approach of site rankings and field evaluations, tailings and waste rock disposal sites were selected and recommended for the preliminary design phase of the permitting and project development process. The site selection study provided the documentation necessary to justify the use of these sites for waste disposal and enabled Homestake Mining Co. to anticipate and integrate environmental concerns with agency requirements into the planning process.

Jan 1, 1986

By R. M. Raymond

THE Mining Section of The National Safety Council recently sent out a questionnaire to operators, regarding the class of rope used, specifications required or obtained, factors of safety observed, methods of fastening ropes, lubrication, inspection, and points observed when rope is to be discarded. The answers received from this questionnaire, largely from metal mines, give interesting information, from which recommendations for safety practice on hoisting ropes are drawn. DEPTH OF MINE The depth in the majority of cases noted is from 1000 ft. to 1500 ft. (304 to 457 m.) and records come from a number hoisting from depths of 2000 to 3000 ft. Hoisting is generally done in balance, with a few companies using counterweights. Seldom, more than two shifts are occupied in hoisting. A number of large operators limit the shift for engineers to 6 hr. A few of the larger operators have separate hoists for men and supplies, with a higher class rope for men. The range of loads varies from 7 to 17 tons and greater in a few cases, with a balanced weight of 4 to 7 tons.

Jan 2, 1922

By J. H. Brophy, A. I. Prill

The authors have previously investigated the solid-state activated sintering of tungsten powder with various Ni-Cu additions.' Log shrinkage vs log time plots showed changes in slope from 4 to x at intermediate times during the sintering process. This was attributed to a change in the rate-controlling mass-transport process from solution of tungsten into the tungsten-alloy interface to diffusion of tungsten in this interface. It was postulated that the melting of the activating layer should not affect this transport process. However, the superposition of rearrangement due to the presence of a liquid phase complicates the data analysis. It is the purpose of this note to apply the analysis of Prill, Hayden, and rohy' to account for "rearrangement shrinkage'? in liquid-phase sintering of the W-Ni-Cu system. This results in "solution-precipitation stage" shrinkage plots which were comparable to those obtained in solid-phase activated sintering of the same system. If one assumes total shrinkage to be the sum of rearrangement and solution precipitation, the effects can be isolated easily.2 This results in the general equation:

Jan 1, 1967

By H. Herman, C. Chiou, M. E. Fine

From variation in Young's modulus and Vicker's hardness during GPl zone formation in A1-2 at. pct Cu the following was observed: 1) the presence of grain boundaries does not have any perceptible? effect on the aging reaction; 2) the modulus charge is orientation dependent; 3) the activation energy for zone growth is confirmed to be 11 * 1 kcal per mole; 4) reaging after reversion is preceded by an incubation time that varies with temperature. An analysis is applied to the present data and to data of other workers and kinetic laws dependent on the quenching rate are determined. In Al-base Cu alloys the decomposition product of a supersaturated solid solution at low temperatures (for example 25°C) and the first product at moderate temperatures (for example 150oC) are Guinier-Preston zones of the first kind (GPI).' These zones are nonideal and are thought Jo 'Onsist roughly of sheets of Cu atoms up to 150A in diam and one or two atoms thick.' The kinetics of the reaction, ass — a2

Jan 1, 1961

By T. S. Fuller

The work of D. J. McAdam, Jr.1,2 at the U. S. Naval Engineering Experiment Station, Annapolis, Md., on what has been called by him "corrosion-fatigue" has focussed the attention of the engineering profession in general, and of those interested especially in the study of corrosion in particular, on the importance of making tests which will indicate as nearly as possible what can be expected from a given material in service. Pitting is unquestionably the chief agent operating so tremendously to reduce fatigue limits, but in the light of previous work3, 4, 5, 6, 7, 8 it is fair to assume that absorbed hydrogen resulting from the action of the corroding medium upon steel may, under certain conditions, have a perceptible influence. The experiments described in this paper deal more precisely with stressless corrosion, or "prior-corrosion fatigue,"9 and have been carried out to test such an assumption, to segregate, if possible, the effect of pitting from that of absorbed hydrogen, and although very preliminary in nature they indicate results which are striking.

Jan 1, 1929

By T. S. Fuller

The work of D. J. McAdam, Jr.1,2 at the U. S. Naval Engineering Experiment Station, Annapolis, Md., on what has been called by him "corrosion-fatigue" has focussed the attention of the engineering profession in general, and of those interested especially in the study of corrosion in particular, on the importance of making tests which will indicate as nearly as possible what can be expected from a given material in service. Pitting is unquestionably the chief agent operating so tremendously to reduce fatigue limits, but in the light of previous work3, 4, 5, 6, 7, 8 it is fair to assume that absorbed hydrogen resulting from the action of the corroding medium upon steel may, under certain conditions, have a perceptible influence. The experiments described in this paper deal more precisely with stressless corrosion, or "prior-corrosion fatigue,"9 and have been carried out to test such an assumption, to segregate, if possible, the effect of pitting from that of absorbed hydrogen, and although very preliminary in nature they indicate results which are striking.

Jan 1, 1929

By P. D. Merica, A. N. Finn, R. G. Waltenberg

CeRtain compositions of the light, i.e., aluminum-rich, alloys of aluminum with magnesium and copper have become quite well known within the past ten years under the name of duralumin. These alloys are used for rolling and forging and can be so treated as to develop quite remarkable mechanical properties. Thus a properly heat-treated alloy containing about 4 per cent. of copper and about 0.5 per cent. of magnesium, rolled into sheet or rod, will have a tensile strength of approximately 55,000 1b. per sq. in. (3866 kg. per sq. cm.) with an elongation in 2 in. (50.8 mm.) of about 15 per cent. This alloy, duralumin, was developed by Wilm,1 and its properties more fully described by Cohn.2, The authors considered it worth while to investigate the mechanical possibilities of the light alloys of two somewhat analogous ternary series; namely, of aluminum-magnesium-nickel and aluminum-magnesium-manganese, to study the effect of variation of composition upon mechanical properties within the alumimum-rich group of the aluminum-magne-

Jan 1, 1921

By T. T. Chen, P. Pint

Based on the mineralogy, phase characteristics and compositions of the smelter feed, the smelter products and the smelter wastes, the sources and distributions of mercury and arsenic in the Afton copper smelter, Kamloops, British Columbia have been determined. Of the total mercury In the feed, approximately 33% is in solid solution in tennantite, 51% is in native copper and 16% occurs as mercurian silver. Arsenic in the feed occurs mainly as tennantite. Under current smelting conditions, 99.6% of the total mercury In the feeds enters the off-gas cleaning system. From this off-gas, about 1% of the total mercury, occurring as dust, is recirculated to the flotation concentrate; 4.6% of the total mercury is contained in SO2 scrubber sludge which is discharged to tailings. Approximately 78% of the total arsenic in the smelter reports in the copper products; 20% is incorporated in the dust and slag which are subsequently recirculated to the mill. Only 1.8% is rejected as scrubber sludge, and less than 0.2% 1s released to the mercury scrubber.

Jan 1, 1984

By Christopher G. Atwater

The object of this paper is to describe and discuss the progress that has been made, up to the present date, in the development of the modern by-product coke-oven. There are few members of the Institute who have not heard more or less of the by-product oven-installation, and there are many whose acquaintance with it is intimate and practical. Since the general opinion on the subject has hardly become crystallized as yet, it is hoped that this paper will at least furnish matter for discussion. In order to obtain an idea of the present status of the industry in the principal iron-producing countries, the following table has been prepared : Table Showing Proportion of Coke Made in By-Product Ovens in Various Countries. United Kingdom (1898, Mr. George Beilby). Short Tons. Per Cent. Coal coked in by-product ovens,. .. 1,400,000 7.9 Coal coked in blast-furnaces with by-product recovery,.......2,240,000 12.7 Coal coked in non-by-product ovens,. . 14,000,000 79.4

Jan 1, 1903

By Rollyn P. Jacobson

The town of Pacific, in Jefferson County, Mo., is 27 miles west of St. Louis. Since the area lies entirely on the flood plain of a cut-off meander of the Meramac River, it was considered a likely environment for accumulation of commercial quantities of sand and gravel. Excellent transportation facilities are afforded by two major railways to St. Louis, and ample water supply for washing and separation is assured by the proximity of the river. As a large washing and separation plant was planned, the property was evaluated in detail to justify the high initial expenditure. An intensive testing program using both geophysical and drilling methods was designed and carried out. The prospect was surveyed topographically and a 200-ft grid staked on which electrical resistivity depth profiles were observed at 130 points. The Wenner 4-electrode configuration and earth resistivity apparatus* were used. In all but a few cases, the electrode spacing, A, was increased in increments of 1% ft to a spread of 30 ft and in increments of 3 ft thereafter.

Jan 2, 1955

By G. H. Walrod, J. M. Mutmansky, Y. J. Wang

The selection of a shaft size for ventilation purposes is a classic problem of concern to mining engineers. This presentation is concerned with the sizing of conventionally-sunk circular shafts with concrete or shotcrete linings. Costs of sinking shafts of three different depths, from 150 m to 300 m (500 ft to 1000 ft), and six different diameters, from 4.27 m to 7.32 m (14 ft to 24 ft), were obtained through questionnaires to shaft contractors. The primary objective of the economic model presented is the balancing of detailed annual capital and operating costs to achieve the minimum overall cost of the shaft installation over its life. The economic model is similar to previous analyses but treats several of the individual cost categories in an updated fashion. Included in the paper is a detailed analysis of the effects of varying power costs on optimal shaft size. Also included are a statistical analysis of current shaft costs and comments on the choice between shotcrete and concrete linings.

Jan 1, 1979

By Robert A. Melton

Since many of the easily mined, continuous, thick coal seams in the Appalachian Region have been exhausted, new exploration and mining is being directed toward less continuous seams that are under more cover and are more difficult to mine. The direct results of this are that more money and time and more expertise and data are needed to plan and open new coal mines today. It is also becoming apparent that the old methods of assimilating and preparing information needed for mine planning are inadequate to meet the needs of today's modern mining engineer, especially in the areas of data gathering, storage, retrieval, preparation, and interpretation. The system described here allows assimilation of old and new core data in a relatively quick, accurate, and efficient manner. The system is a set of computer assisted procedures consisting of the following four basic steps: 1) raw data collection, computer input, storage, and graphic preparation, 2) geologic profile correlation and establishment of seam continuity, 3) computerized data posting of important seam parameters, 4) geologic and planimetric analysis for mine planning.

Jan 1, 1977

By Frank C. Roe

Two cogent and ubiquitous facts have supported a constant search by the ore processing industry for better wear resistant materials in equipment. First, designs and types of equipment change or improve continually to meet the economic and physical demands of different and/or leaner ores. Second, practically all equipment is subject to impact and abrasion conditions that probably are more severe and extensive than in any other industry. Development and testing by operators and equipment manufacturers alike, has produced an extensive variety of longer lasting metal alloys, rubber, plastics, ceramics and other materials to improve equipment performance under different specific conditions. The need for diversified materials becomes obvious upon the simple realization that no two beneficiation operations are identical. Among the variables in the handling of ore are: 1. Size and weight of ore particles. 2. Hardness and sharpness of ore particles. 3. Concentration of ore particles in liquid or gas suspension. 4. Velocity and direction of particle impact toward equipment surface. 5. Coefficient of friction between ore particles and equipment surface. 6. Temperature of operation. 7. Chemical environment of operation.

Jan 12, 1967

By David D. Rabb

Under the auspices of the Atomic Energy Commission, the Lawrence Radiation Laboratory of the University of California analyzed an experiment to provide information as to whether the chimney of broken rock produced by a deeply buried nuclear explosive could be "drawn" by conventional techniques. Since many low-grade disseminated ore-bodies occur in a granite media, the experiment took place in a granodiorite-quartz monzonite intrusive porphyry in the Nevada Test Site as a follow-up to the Department of Defense's Hardhat detonation in February 1962. For emplacement of the nuclear device, a 12 ¼ - in. pilot hole was reamed to a diameter of 44 in. and a depth of 950 ft in one pass using a Hughes multiple-cluster rotary bit. It was then cased to 36 in. ID. The center of the explosive device was located 938.85 ft below the collar. The yield of the device was predicted to be 5 kilotons, or an equivalent of 5000 tons of TNT; the yield was later confirmed by chemical means to be 5.4 kilotons.

Jan 3, 1964

By P. D. Merica

Certain compositions of the light, i:e., aluminum-rich, alloys of aluminum with magnesium and copper have become quite well known within the past ten years under the name of duralumin. These alloys are used for rolling and forging and can be so treated as to develop quite remarkable mechanical properties. Thus a properly heat-treated alloy containing about 4 per cent. of copper and about 0.5 per cent. of magnesium, rolled into sheet or rod, will have a tensile strength of approximately 55,000 lb. per sq. in. (3866 kg. per sq. cm.) with an elongation in 2 in. (50.8 mm:) of about 15 per cent. This alloy, duralumin, was developed by Wilm,1 and its properties more fully described by Cohn.2 The authors considered it worth while to investigate the mechanical possibilities of the light alloys of two somewhat analogous ternary series; namely, of aluminum-magnesium-nickel and of aluminum-magnesium-manganese, to study the effect of variation of composition upon mechanical properties within the alumimum-rich group of the aluminum-magne-

Jan 7, 1919